Pressure-developing device and recording device

ABSTRACT

A pressure developing unit moving along a surface of a cycolor medium to perform pressure development has a first rotating member that faces a platen and is capable of performing pressure development of a recording sheet, and a second rotating member that is capable of transmitting a load applied to the first rotating member to a carriage shaft. If the pressure developing unit is moved along the carriage shaft, the first and second rotating members move by revolving along the recording sheet and the carriage shaft respectively in a direction in which the pressure developing unit moves, so that there is no possibility of sliding friction being caused. The pressure developing unit can be moved along the carriage shaft causing only rolling friction. Thus, it is possible to reduce the size of a motor for moving the pressure developing unit and to realize thereby a recorder that is compact in size and low in power consumption.

TECHNICAL FIELD

The present invention relates to an apparatus for performing pressuredevelopment of a recording sheet such as a Cycolor medium thatnecessitates pressure development in a process of producing a colorprint, and it also relates to a recorder having such an apparatus.

BACKGROUND ART

A color printing method for implementing a process of pressuredevelopment is known. This method includes the steps of exposing aphotosensitive medium coated with minute capsules containing colorforming materials, activating or deactivating the capsules in accordancewith an image, and rupturing the activated capsules by pressurizing theexposed medium. A cycolor medium 1 as illustrated in FIG. 14 is anexample of such a medium. The cycolor medium 1 is a medium having a film2 made of polyester or the like, the film 2 being coated with aninfinite number of microcapsules called cyliths 3a to 3c. Each of thecyliths 3a to 3c contains one of color forming materials of cyan,magenta and yellow and a sensitive material called a photo initiatorthat is sensitive to light of a specific wavelength. The photo initiatorcontained in each of the cyliths 3a to 3c hardens if it is irradiatedwith light of a specific wavelength, for example, light of acomplementary color of each of the cyliths 3a to 3c. Accordingly, it ispossible to deactivate the color forming reaction of a color formingmaterial contained in a cyliths depending on the wavelength of lightemitted.

The cycolor medium 1 undergoes pressure development in which the cyliths3a to 3c of three different colors are irradiated with light andsubjected to a high pressure so that the activated cyliths 3a to 3c arecrushed. The development method of this kind causes a chemical reactionbetween the color forming materials contained in the cyliths 3a to 3cand a transparent image-receiving layer called a receiver 4 that is madeof polyester or the like, thereby a predetermined color image isrecorded (printed) on the cycolor medium 1 which is a recording medium.For example, if only red light is emitted, only the photo initiatorcontained in the cyliths 3a of cyan hardens. The cyliths 3b of magentaand the cyliths 3c of yellow are crushed due to pressurization, wherebythe color forming materials of magenta and yellow develop theirrespective colors. Thus, those color-forming materials are mixed todevelop red color. Similarly, if green light is emitted, the cyliths 3aof cyan and the cyliths 3c of yellow are crushed to develop green color.If blue light is emitted, the cyliths 3a of cyan and the cyliths 3b ofmagenta are crushed to develop blue color.

Thus, a photosensitive medium such as the cycolor medium 1 needs to besubjected to pressure development after being exposed. As a pressuredeveloping apparatus therefor, pressure means composed of a pair ofrollers that are vertically disposed is generally employed. By conveyingthe cycolor medium (medium) 1 into a gap between the rollers andentirely pressurizing the medium 1, pressure development is performed.

To sufficiently pressurizing the medium using such rollers, thosecomponents which are strengthened enough to endure a comparatively highdeveloping pressure, such as rollers, bearings, frames and the like arerequired. To homogeneously pressurizing the entire medium, at least oneof the rollers needs to be shaped like a drum by being subjected to acrowning processing. Thus, the pressure developing apparatus becomeslarger, heavier and more expensive.

In view of such backgrounds, it has been considered to replace theconventional pressure developing apparatus employing rollers with apressure developing apparatus that pressurizes a recording sheet by asmall ball (development ball) reciprocating with respect to the surfaceof a medium (printing sheet or recording sheet) in scanning directions.Since the development ball contacts a point of the surface of therecording sheet, the contact area between the development ball and therecording sheet is very small. Thus, by a small force, it is possible tosignificantly enhance a pressure per area, so that the pressuredeveloping apparatus can be made smaller and lighter than thoseemploying rollers. Further, since the development ball does notnecessitate a special processing such as a crowning processing, thepressure developing apparatus and the recorder employing the pressuredeveloping apparatus can be provided at low costs.

FIG. 15 illustrates an example of the recorder (printer) employing apressure developing apparatus having a development ball. The recorder 10has an exposure unit 20 for exposing the aforementioned cycolor medium 1to form an image, a pressure developing apparatus 30 moving along thesurface of the medium 1 exposed by the exposure unit 20 in scanningdirections that are perpendicular to a sheet-conveying direction A toperform pressure development, a slab-like face plate (supportive plateor platen) 11 disposed above the pressure developing apparatus 30, and asheet-conveying mechanism 60 for conveying the medium 1 exposed by theexposure unit 20 toward the pressure developing apparatus 30 bysandwiching the medium 1 between a main roller 61 and an auxiliaryroller 62. The exposure unit 20 and the pressure developing apparatus 30are mounted on a carriage 53, which reciprocates along carriage shafts51 and 52 extending in the scanning directions by drive means such as amotor 6 and a timing belt 7. The exposure apparatus 20 reciprocates inthe scanning directions to expose the medium dot by dot, thus forming animage. Then the pressure developing apparatus 30 sequentially performpressure development of the exposed medium 1, thus outputting acolor-printed cycolor medium. As a matter of course, the arrangement ofthe platen 11 and the pressure developing apparatus 30 can be reversed.Further, it is also possible to horizontally arrange the platen 11 andthe pressure developing apparatus 30.

The exposure apparatus 20, which can employ an LED head 21 having LED'scapable of irradiating the medium 1 with three different lights of red(R), green (G) and blue (B), is moved by the carriage 53 to irradiateeach of the cyliths 3a to 3c forming each dot with a light of a suitablecolor. Thus, it is possible to deactivate the cyliths 3a to 3c dot bydot on the basis of image data sent from a personal computer or thelike, and to record the image on the cycolor medium 1 (to expose thecycolor medium 1).

The pressure developing apparatus 30 moves together with the exposureapparatus 20 and performs pressure development of the exposed medium 1that has been conveyed by the sheet-conveying mechanism 60. The pressuredeveloping apparatus 30 has a rectangular parallelepiped housing 31extending toward the medium 1 and a development ball 39 partiallyprotruding from the side of the medium 1 of the housing 39. Thedevelopment ball 39 is pressed against the platen 11 by a spring 37accommodated in the housing 31. It is possible to perform pressuredevelopment of the medium 1 by sandwiching the medium 1 between theplaten 11 and the development ball 39.

The pressure developing apparatus 30 employing the development ball 39as described above can pressurize the medium 1 over an extremely small(local) area that is almost considered to be a spot or a point. As thepressure developing apparatus 30 moves, the point to which a pressure isapplied continuously moves. Thus, it is possible to ensure a pressurelevel sufficient to perform development with a relatively small force asobtained from a simple elastic body such as a thin spring or an elasticmechanism. Thus, it is unnecessary to use a large roller, whereby theentire recorder can be significantly reduced in size and weight.Further, since the development ball moves by revolving along the surfaceof the medium 1, it is possible to pressurize the medium 1 withoutcausing a damage thereto. Therefore, by employing the pressuredeveloping apparatus 30 thus constructed, it becomes possible to reducethe recorder 10 in size and weight, and to provide a recorder that iscapable of outputting a high-quality color print at low costs.

However, it has been considered to further improve the aforementionedpressure developing apparatus 30 to make it possible to provide arecorder that is more compact and less expensive. For example, thepressure developing apparatus as illustrated in FIG. 15 is designed suchthat the carriage shaft 52 receives a reaction force generated inperforming pressure development via the carriage 53 and that thepressure developing apparatus 30 moves along the carriage shaft 52.Accordingly, the reaction force for performing pressure developmentincreases a frictional force generated between the carriage 53 and thecarriage shaft 52. To reciprocate the carriage 53 smoothly along thecarriage shafts 51 and 52, it is necessary to prepare a drive motorhaving sufficient large outputs to counteract the frictional force. Adrive motor with a great driving force is bulky and requires a largeinstallation space. Therefore, an attempt to ensure an installationspace for such a high-output drive motor poses a serious problem inreducing the size of the recorder.

The drive motor with high outputs is accompanied by high powerconsumption. In the recorder employing the cycolor medium 1, theexposure apparatus is a contactless type and can be reduced in size, andexpendable supplies such as a ribbon, a toner and the like are notrequired. Thus, the recorder of this manner can be reduced to a sizegenuinely suited for conveyance. To realize a portable recorder, it isrequired that the recorder be capable of operating for a long period oftime with a power source of limited energy such as a battery. Hence, itis necessary to reduce the electric power consumed by a drive motor tothe minimum possible value. In addition, since a large motor requires ahigh cost, it is desirable to use a low-power motor with a view toreducing the cost of the recorder.

Therefore, for the purpose of reducing the size and cost of the recorderas well as power consumption, it is indispensable to downsize the drivemotor. It is thus an object of the present invention to provide apressure developing apparatus that can be driven with less power andapply a sufficient pressure. That is, the present invention aims atproviding a pressure developing apparatus that can be moved in scanningdirections with a small force and develop a high-quality color print bysufficiently pressurizing the medium. It is another object of thepresent invention to downsize the recorder by making the pressuredeveloping apparatus to be installed in a narrow space. It is stillanother object of the present invention to reduce the motor powernecessary for moving the carriage including the pressure developingapparatus and to realize a compact and low-cost recorder that is low inpower consumption and suited for conveyance.

DISCLOSURE OF THE INVENTION

A pressure developing apparatus according to the present invention isprovided with a first rotating member such as a development ball thatmoves along a recording sheet while pressurizing the recording sheet,and a second rotating member that can move by revolving along asupportive member such as a carriage shaft, whereby the second rotatingmember transmits a load applied to the first rotating member to thesupportive member. That is, the pressure developing apparatus accordingto the present invention that moves along the supportive member forpressuring the recording sheet is characterized by including the firstrotating member that moves by revolving to pressurize the recordingsheet and the second rotating member that moves by revolving withrespect to the supportive member and can transmit a load applied to thefirst rotating member to the supportive member. By providing thepressure developing apparatus comprising the second rotating member, itis possible to move the first rotating member with respect to thesupportive member not by sliding friction but by rolling friction of thesecond rotating member. Therefore, the pressure developing apparatus canbe moved along the supportive member with a small force.

Since the frictional force generated relative to the supportive memberbecomes small, the first rotating member can be smoothly moved along thesupportive member with a small force and at a substantially constantspeed. Therefore, the speed at which the first rotating member moves andthe pressure applied to the recording sheet hardly fluctuate, whereby itis possible to pressurize the recording sheet sufficiently and morehomogeneously. As a result, it is possible to develop a high-qualitycolor print.

Thus, the pressure developing apparatus according to the presentinvention can be moved along the supportive member such as the carriageshaft by a low-output motor, and, the pressure developing apparatus ofthis invention can provide a high-quality image. Therefore, ahigh-performance recorder can be provided using a compact and low-outputmotor, whereby it is possible to reduce the size of the recorder as wellas electric power consumption. That is, the recorder having: thepressure developing apparatus according to the present invention; anexposure apparatus for exposing a photosensitive recording sheet; asheet-conveying apparatus for conveying the recording sheet exposed bythe exposure apparatus to the pressure developing apparatus; and adriving apparatus for causing the pressure developing apparatus toreciprocate along a supportive member extending in scanning directionsthat are substantially perpendicular to a sheet-conveying direction ofthe sheet-conveying apparatus, makes it possible to downsize the drivingapparatus by reducing power therefor. It is thus possible to providerecorder that is the size is compact, low in power consumption andsuited for conveyance. Since this recorder is low in power consumption,it is possible to further downsize the recorder including a power sourcesection for accommodating batteries and the like.

As the first rotating member of the pressure developing apparatusaccording to this invention, it is possible to employ a member that isshaped so as to contact the recording sheet locally and continuously,such as a ball, a roller of a narrow width, a disc or the like. Toachieve a state of continuous contact with the recording sheet over aneven smaller area so that a high pressure can be easily obtained, it isalso possible to employ a rotary member that has ring-like protrusionson its surface. By localizing the contact area between the rotatingmember and the recording sheet, it is possible to provide a pressuredeveloping apparatus that is more compact in size and more excellent indeveloping performance. It is also possible that on a sheet-supportivemember, which supports the recording sheet from a side opposite to thefirst rotating member, a protrusion is provided extending in a directionin which the first rotating member moves in an area where the firstrotating member moves. In this arrangement, the area of the recordingsheet pressurized by the first rotating member is also localized.Therefore, it is possible to provide a pressure developing apparatusthat is compact and excellent in developing performance.

The second rotating member can be disposed between the first rotatingmember and the supportive member such that the second rotating membercan move by revolving while being in contact with the first rotatingmember and the supportive member. As the pressure developing apparatusmoves, the first rotating member moves by revolving in a direction inwhich the pressure developing apparatus moves while pressurizing therecording sheet, and the second rotating member also moves in thedirection in which the pressure developing apparatus moves while beingin contact with the supportive member. Since the first rotating memberis directly in rolling contact with the second rotating member, there isno sliding friction caused when the pressure developing apparatus moves.Thus, the pressure developing apparatus can be moved with a considerablysmall force. Consequently, it is possible to further reduce the outputsof the drive motor necessary for moving the pressure developingapparatus.

Although this pressure developing apparatus is designed such that thefirst rotating member revolves relative to the supportive member in adirection opposed to the direction in which the pressure developingapparatus moves, the second rotating member, which revolves relative tothe supportive member in the direction in which the pressure developingapparatus moves, can directly support the first rotating member from ofthe supportive member. Thus, it is easy to ensure a sufficient pressurelevel, and it is unnecessary to employ an intermediate member, such as aspring, for transmitting a load applied to the first rotating member tothe supportive member. Consequently, the installation space for thespring can be omitted, whereby the pressure developing apparatus can befurther reduced in size.

To apply stable pressure on the recording sheet over a long period oftime in consideration of factors such as erection tolerances of thepressure developing apparatus or the recorder, abrasion of the rotarymembers and the like, it is desirable to ensure or compensate for apredetermined level of developing pressure using an elastic member suchas a spring. Further, since the recording sheet has a certain thickness,when the pressure developing apparatus is moved across the recordingsheet from one end to the other end, a gap formed between the pressuredeveloping apparatus and the sheet-supportive member that supports therecording sheet from the side opposite to the first rotating member,fluctuates depending on whether the recording sheet is in the gap ornot. Therefore, it is necessary to enable a predetermined pressure to beapplied even if the gap formed between the first rotating member and thesheet-supportive member somewhat fluctuates. Hence, in the case ofadopting the above pressure developing apparatus in which the first andsecond rotating members are directly connected with each other, thepressure developing mechanism is desirably that having a pressuresupportive apparatus for elastically supporting the sheet-supportivemember to pressurize the first rotating member.

However, if the sheet-supportive member is elastically supported, thesheet-supportive member may subtly vibrate when the pressure developingapparatus passes an edge of the recording sheet. The pressure applied tothe recording sheet thereby fluctuates, so that the image developed onthe edge portion of the recording sheet may suffer color nonuniformity.To inhibit the generation of such a color nonuniformity (shade,irregularity), it is desirable to provide a transmission apparatus forelastically transmitting a load applied to the first rotating member tothe second rotating member. By this arrangement, the rotary member oflight weight can absorb the unevenness (gap difference) at the edgeportion of the recording sheet, so that it is possible to inhibitpressure fluctuations and to form (develop) a color image exhibiting ahigh color developing quality even on the edge portions of the recordingsheet. Further, since the unevenness resulting from the edge portion ofthe recording sheet can be absorbed by the first rotating member havinglight weight, it is advantageously possible to further reduce thedriving power required to move the pressure developing apparatus.

To transmit a load applied to the first rotating member to the secondrotating member, it has been considered to couple the first rotatingmember to the second rotating member via an elastic member such as aspring. However, if the elastic member is linearly disposed between thefirst and second rotating members, the distance between the first andsecond rotating members becomes longer, whereby it may become difficultto downsize the pressure developing apparatus. Thus, with a view toreducing the recorder accommodating the pressure developing apparatus insize, particularly in thickness, it is desirable to establish anarrangement in which a center of rotation of the second rotating memberis offset relative to a center of rotation of the first rotating member.To transmit a load applied to the first rotating member to the secondrotating member, it is possible to employ, for example, a transmissionapparatus having arms for supporting the first and second rotatingmembers respectively, which arms are coupled to each other by an elasticmember.

It is also effective to arrange the first rotating member and two piecesof the second rotating member such that the first rotating member movesby revolving while invariably contacting these two second rotatingmembers. In this manner, the arrangement in which the centers ofrotation of the first and second rotating members are offset withrespect to each other is established. Thus, as described above, it ispossible to provide a pressure developing apparatus that can be disposedwithin a narrow space. It is also possible to provide plural pieces ofthe first rotating member or to arrange plural sets of both the firstand second rotating members. In addition, by installing a holdingapparatus for applying an elastic force in such a direction as to reducethe distance among the first rotating members or among the secondrotating members, the difference of stage at the edge of the recordingsheet can be smoothly absorbed.

It is also effective to provide a guide member along a direction inwhich the first rotating member moves and the guide member can bedeformed into a substantially smooth shape corresponding to a crosssection of the recording sheet. In passing the edge of the recordingsheet, the first rotating member moves along the guide member deformed asmooth shape, thus the vibration of the sheet-supportive member or thepressure developing apparatus can be damped. Therefore, it is possibleto inhibit the generation of color irregularities. The guide member maybe a metallic wire, a thin metallic member having a shape of a strip, orthe like. However, in the case where the first rotating memberpressurizes the recording sheet via such a guide member, the contactarea between the guide member and the recording sheet increases, wherebyit becomes necessary to increase the force applied by the first rotatingmember. Hence, it is desirable to employ as the guide member a number ofsmall divided pieces ranging along a direction in which the firstrotating member moves, and to pressurize each of the small pieces usingthe first rotating member so as to prevent the pressure from beingdispersed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a recorder employing a pressuredeveloping unit and a pressure developing mechanism according to anembodiment of the present invention.

FIG. 2 is a perspective view illustrating a carriage of the recorder inFIG. 1.

FIG. 3 illustrates a pressure developing mechanism in FIG. 1 in a crosssection perpendicular to scanning directions (moving directions).

FIG. 4 is a top view of the pressure developing unit illustrated in FIG.1.

FIG. 5 illustrates the overall structure of the pressure developingmechanism as illustrated in FIG. 1 in a cross section taken along thescanning directions (moving directions).

FIG. 6 illustrates another example of the pressure developing mechanismaccording to the present invention in a cross section perpendicular tothe scanning directions (moving directions).

FIG. 7 illustrates the movement of the pressure developing mechanismemploying the pressure developing unit illustrated in FIG. 5 in thevicinity of an edge portion of a recording sheet.

FIG. 8 schematically illustrates an example that prevents fluctuationsof a developing pressure applied to the edge portion of the recordingsheet.

FIG. 9 schematically illustrates an example of the pressure developingmechanism capable of inhibiting fluctuations of the pressure applied tothe edge portion of the recording sheet.

FIG. 10 schematically illustrates another example of the pressuredeveloping mechanism according to the present invention.

FIG. 11 schematically illustrates still another example of the pressuredeveloping mechanism according to the present invention.

FIG. 12 schematically illustrates an example of the pressure developingmechanism according to the present invention in which a guide member isused.

FIG. 13 schematically illustrates still another example of the pressuredeveloping mechanism according to the present invention.

FIG. 14 is an illustrative view schematically illustrating a cycolormedium.

FIG. 15 schematically illustrates the overall structure of a recorderhaving a pressure developing apparatus employing a development ball.

BEST MODES FOR CARRYING OUT THE INVENTION

First Embodiment

A recording apparatus according to an example of the present inventionwill hereinafter be described with reference to the accompanyingdrawings. FIG. 1 schematically illustrates the structure of the recorderhaving a pressure developing mechanism 90 of the present invention. Therecorder 10 of the present embodiment is a recorder for a cycolor medium1, as is the case with the recorder described based on FIG. 15. In therecorder 10, an exposure unit 20 and a pressure developing unit 70 arelaid on a carriage 53 and able to move in scanning directionsperpendicular to a sheet-conveying direction A of a sheet-conveyingmechanism 60. The exposure apparatus 20 moves in the scanning directionsby means of the carriage 53 and exposes the cycolor medium (medium) 1 asa recording sheet. The exposed medium 1 is conveyed toward the pressuredeveloping mechanism 90 comprising a platen 11 and the pressuredeveloping unit 70 moving in the scanning directions along a surface ofthe platen 11. The pressure developing unit 70 reciprocates along thesurface of the medium 1 while applying pressure thereto, so that anexposed color image is developed. Those components that are commonlyused in the recorder described based on FIG. 15 will hereinafter bedenoted by the same reference numerals, and the detailed descriptionthereof will be omitted.

The pressure developing unit 70 employed in the recorder 10 of thisembodiment comprises first and second rotating members 71 and 72 whichare vertically disposed. These rotary members 71 and 72 are accommodatedin a housing 79 and mounted on the carriage 53 together with theexposure unit 20, so that they can move in the scanning directions. Whenmoving, the first rotating member 71 is in contact with the plate-likeplaten 11 that is a sheet-supporting member. The first rotating member71 is a member for performing pressure development of the medium 1 bysandwiching it between the platen 11 and the first rotating member 71.The second rotating member 72 moves by revolving between the carriageshaft 52, which is a supportive member, and the first rotating member71, contacting with the first rotating member 71 and the carriage shaft52. The second rotating member 72 is a member for transmitting a loadapplied to the first rotating member 71 to the carriage shaft 52.

The pressure developing unit 70 of this embodiment allows the secondrotating member moving by revolving along the carriage shaft 52 todirectly receive a load applied to the first rotating member 71 whichmoves with pressurizing the recording sheet 1. Hence, while the firstrotating member 71 performs pressure development, it is possible to movethe pressure developing unit 70 along the carriage shaft 52 not bysliding friction but by rolling friction of the second rotating member72. A reaction force of a pressure applied to the platen 11 by the firstrotating member 71 is transmitted by the second rotating member 72 thatmoves by rotating on the carriage shaft 52, therefore the frictionalresistance becomes extremely small. Hence, the driving power for movingthe carriage 53 in the scanning directions, while ensuring a pressureforce sufficient for development, is much smaller than the driving powerof the recorder as illustrated in FIG. 15, in which the pressuredeveloping unit moves by sliding friction. Accordingly, it is possibleto reduce outputs power of a drive motor 6 for driving the carriage 53in the scanning directions, and to reduce an installation space for amotor in the recorder 10 by downsizing the motor. By decreasing requiredpower of the motor, it is possible to reduce the costs of the motor andan accompanying power source. Hence, the recorder 10 being compact andlight in weight can be provided at low costs. In addition, since asmaller output drive motor can drive the carriage 53, it is possible tosignificantly reduce power consumption and the recorder can be used bybatteries' power practically. Accordingly, the compact and low powerconsumption recorder suitable for portable use can be provided by theinvention.

Further, in the pressure developing unit 70 of this embodiment, thesecond rotating member 72 can transmit a load applied to the firstrotating member 71 to the carriage shaft 52 by rotating on the carriageshaft 52 in a direction to the pressure developing unit 70 moves.Therefore, it is unnecessary to temporarily receive the load applied tothe first rotating member 71 using a spring or the like for transmittingthe load to the carriage shaft 52. Accordingly, it is possible to omitan installation space for an intermediate member, such as spring, forobtaining a pressure force to be applied, so that the pressuredeveloping unit 70 becomes more compact. Hence, it is possible toachieve an entirely compact and thin structure of a recording mechanism50 of the recorder, and it is possible to reduce the size and price ofthe recorder 10.

The pressure developing unit 70 of the pressure developing mechanism 90of this embodiment will be described in detail with reference to FIGS.2, 3, 4 and 5. FIG. 2 is a perspective view schematically illustratingthe structure of the pressure developing unit 70, which is shown withthe exposure apparatus 20 in that figure. The recording mechanism 50 ofthe recorder of this example comprises two carriage shafts 51 and 52extending in parallel with scanning directions B. Supported by thecarriage shafts 51 and 52, the carriage 53 reciprocates in the scanningdirections B. The pressure developing unit 70 and the exposure unit 20are mounted on the carriage 53. The exposure unit 20 has an exposurehead 21 on which LED's 22 of red (R), green (G) and blue (B) aredisposed, so that the exposure head 21 is moved by the carriage 53 inthe scanning directions B. The exposure head 21 is connected with acontrol board (not shown) via a flexible cable 23 and lights upappropriate LED's 22 of each color with a predetermined brightness foreach dot of a recording sheet, based on image data supplied from apersonal computer or the like, thus irradiating a cyliths on themedium 1. The recorder of the present example is designed to exposecyliths constituting each dot while the exposure head 21 moves in thescanning directions B. Thus, this recorder requires a smaller number ofLED's in comparison with an another recorder in which LED's are arrangedlike an array in the scanning directions. In addition, there is no needto provide a mechanism for controlling differences among individualLED's in comparison with the another recorder. Therefore, the recorderof the present embodiment can print a high-quality image at low costs.

The pressure developing unit 70 of this embodiment comprises a tubularhousing 79 shaped like a rectangular parallelepiped. The housing 79 issupported by an arm 53a extending from one side of the carriage 53 andmoves together with the exposure head 20. In the housing 79 of thepressure developing unit 70 of this embodiment, two pairs of the firstrotating member 71 and the second rotating member 72 are arranged in thescanning directions. It is also possible to pressure develop the cycolormedium 1 using one pair of the first and second rotating members 71 and72. However, taking into account that the tolerance due to such aswobble and/or slight deviations in the housing 79, there is somepossibility to generate an area where no pressure is applied partiallyor an area where only an insufficient pressure is applied. Inconsideration of such circumstances, it is desirable to perform pressuredevelopment by arranging a plurality of combinations of the firstrotating member 71 and the second rotating member 72.

FIG. 3 schematically illustrates, in a cross section perpendicular tothe scanning directions B as the directions of movement, the structureof the pressure developing mechanism 90 of this embodiment having thepressure developing unit 70 and the platen 11. The pressure developingunit 70 of this embodiment has the first and second rotating members 71and 72 vertically disposed within the housing 79. The first rotatingmember 71 comprises a substantially spherical body 73 capable of freelyrotating on an inner wall of the housing 79 and a pressure ring 74vertically protruding like a ring from an outer peripheral surface ofthe body 73. The pressure ring 74 gradually becomes thinner toward a tip75 thereof. When the first rotating member 71 revolves, the pressurering 74 becomes contact with the recording sheet 1 over an extremelysmall area like a point. Therefore, when the first rotating member 71moves, the pressure ring 74 performs pressure development in a thincontinuous line portion of the medium 1. Accordingly, it is possible toapply a high pressure to an extremely small (local) area by sandwichingthe medium 1 between the platen 11 and the pressure ring 74. Therefore,by the smaller force, it is possible to produce a high-quality colorimage that ensures excellent color development.

The second rotating member of the present example comprises a sphericalbody 76 capable of freely rotating on the inner wall of the housing 79and a vertically extending groove 77 formed in an outer peripheralsurface of the body 76. Hence where the first and second rotatingmembers 71 and 72 are vertically arranged inside the housing 79, thepressure ring 74 of the first rotating member 71 is fitted to the groove77 of the second rotating member 72. When the first rotating member 71revolves in one direction, the second rotating member 72 revolves in theother direction and moves along the carriage shaft 52.

FIG. 4 is a top view of the pressure developing unit 70 of thisembodiment. This pressure developing unit 70 accommodates two pairs ofthe first and second rotating members 71 and 72. Hence, the sphericalbodies 73 and 76 are held by corresponding corners 78 that inwardlyprotrude from the inner wall of the housing 79, so that the first andsecond rotating members 71 and 72 can turn at predetermined locations.Therefore, the first rotating members 71 do not interfere with eachother, neither the second rotating members 72.

FIG. 5 illustrates, in a cross section taken along the scanningdirections B of the pressure developing unit 70, the structure of thepressure developing mechanism 90 of the present example. In thispressure developing unit 70, if the carriage 53 moves, for example,toward the right side B1 in FIG. 5, the first rotating member 71 movesby revolving counterclockwise. As a result, the recording sheet 1 issandwiched between the tip 75 of the pressure ring 74 and the platen 11and locally subjected to a comparatively strong pressure force.Consequently, a process of pressure development is performed in whichcyliths in activated state are crushed so as to develop color. On theother hand, the second rotating member 72 moves toward the right side B1along the carriage shaft 52 that is a supportive member, by revolvingclockwise as opposed to the first rotating member 71. Thus, the firstand second rotating members 71 and 72 move along the recording sheet andthe carriage shaft 52 respectively, by revolving in a direction in whichthe pressure developing unit 70 moves. The reaction force of a pressureforce applied to the recording sheet 1 by the pressure ring 74 isdirectly transmitted to the carriage shaft 52 via the second rotatingmember 72. However, since the second rotating member 72 rolls along thecarriage shaft 52 in the moving direction B1, there is no slidingfriction generated between the carriage shaft 52 and the second rotatingmember 72. The only resistance to the movement of the pressuredeveloping unit 70 is rolling friction, which exhibits a significantlylower resistance than sliding friction. Hence, even if a high pressureis applied to the printing sheet 1 by the pressure ring 74, the pressuredeveloping unit 70 can be moved in the scanning directions B with asmall driving force. This also the same in the case where the pressuredeveloping unit 70 moves toward the left side B2 in FIG. 5. In thiscase, the first rotating member 71 performs pressure development byrevolving clockwise. On the other hand, the second rotating member 72transmits a load applied to the first rotating member 71 to the carriageshaft 52, by revolving counterclockwise. Accordingly, the carriage 53 onwhich the pressure developing unit 70 is mounted can be moved with asmall driving force. It is thus possible to utilize a drive motor beinglight in weight, compact in size, low in cost and operable with lowpower.

Further, in this pressure developing unit 70, the second rotating member72 transmits a load to the carriage shaft 52 with rotating in thedirection to the pressure developing unit 70 moves. Thus, it isunnecessary to temporarily receive a load applied to the first rotatingmember 71 revolving in the opposite direction to the carriage shaft 52using an intermediate member such as a spring or the like, then transmitthe load to carriage shaft 52 by sliding along. Therefore, the speed ofthe pressure developing unit 70 does not fluctuate due to a possiblechange in friction coefficient. Nor does the pressure applied to therecording sheet 1 fluctuate. The pressure developing unit 70 can applystable and a high pressure to the recording sheet 1. Accordingly, it ispossible to develop a homogeneous color image without colorirregularities or shade. In addition, it is possible to omit a springfor supporting the first rotating member 71 and a component forsupporting the spring. Therefore, it is possible to reduce the pressuredeveloping unit 70 in size and cost.

Since there is no sliding friction generated between the pressuredeveloping unit 70 and the carriage shaft 52, there is no possibility ofany portion of the pressure developing unit 70 being worn away. Hence,it is possible to provide a pressure developing unit that can apply astable pressure force and having a longer life. By employing thispressure developing unit 70, it becomes possible to provide a recorderthat has high developing quality, being able to make a beautiful colorprint, being long-lasting, highly reliable, small in size and low incost.

Although the first and second rotating members 71 and 72 are verticallydisposed in this embodiment, the present invention is not limited tosuch arrangement. However, in a direction from the printing sheet 1 tothe carriage shaft 52, the first rotating member 71 and the secondrotating member 72 may be arranged in that order. For example, if thecarriage shaft 52 is disposed above the printing sheet 1, thearrangement of the first and second rotating members 71 and 72 isreversed. That is, the first rotating member 71 and the second rotatingmember 72 are disposed in that order in a bottom-to-top direction.Although one of the first rotating members 71 is supported by one of thesecond rotating members 72 in the present example, one of the firstrotating members 71 may be supported by a plurality of the secondrotating members 72, or on the contrary, a plurality of the firstrotating members 71 may be supported by one of the second rotatingmembers 72.

Second Embodiment

In the pressure developing mechanism 90 described above, the pressuredeveloping unit 70 comprising the first and second rotating members 71and 72 having spherical bodies is cited as an example. The first andsecond rotating members may be shaped rotate while being in contact withor being engaged with each other. For example, it is possible to employthe first and second rotating members that are shaped like a roller or adisc, or to employ the first and second rotating members that have gearsengaging each other. FIG. 6 illustrates an another example of the firstand second rotating members. A pressure developing unit 80 included inthe pressure developing mechanism 90 of the present embodiment has aroller-shaped first rotating member 81 and a roller-shaped secondrotating member 82 vertically disposed within a housing 89. The firstand second rotating members 81 and 82 have shafts 83 and 87, and rollerportions 84 and 88 respectively. The shafts 83 and 87 allow the rollerportions 84 and 88 to revolve relative to the housing 89 respectively.

In the roller portions 84 of the first rotating member 81, land portions85 protruding in a circumferential direction are formed on the bothends. A central portion interposed between both the land portions 85constitutes a groove portion 86 that is set back with respect to thelevel of the land portions 85. The land portions 85 on both sides facethe platen 11 and nip the printing sheet 1 so as to pressurize it.

Further, two rows of protrusions 12 extending in a direction in whichthe pressure developing unit 80 moves are provided on the platen 11,which is a supportive plate of this pressure developing mechanism 90. Bysandwiching the printing sheet 1 between these protrusions 12 and theland portions 85, it is possible to pressurize the printing sheet 1 overa small area almost like a point, and to locally apply a high load tothe printing sheet 1. Accordingly, it is possible to apply a pressuresufficient to perform development to the printing sheet 1 using thesmall roller 81 and to reliably perform pressure development so that abeautiful color print can be provided. On the other hand, the grooveportion 86 engages (contacts) the roller portion 88 of the secondrotating member 82 and causes the second rotating member 82 to revolvein the opposite direction. Therefore, a load can be transmitted to acarriage shaft 55 as a supportive member via the second rotating member82. Thus, the pressure developing unit 80 of the present example alsoallows the first rotating member 81 and the second rotating member 82 torevolve relative to the platen 11 and the carriage shaft 55 respectivelyin a direction in which the pressure developing unit 80 goes. Thus, itis possible to substantially reduce the driving power in moving thepressure developing unit 80, and to move the pressure developing unit 80by means of a small motor. The pressure developing unit 80 of thepresent example also has a quite simple structure in which the tworotary members 81 and 82 are vertically disposed. Accordingly, it ispossible to provide a pressure developing unit that is compact,inexpensive, reliable and almost free from quality unevenness ortrouble.

Since the pressure developing unit 80 of this embodiment is designed tomove by rolling or rotating along the surface of the carriage shaft 55,it is unnecessary to employ a cylindrical carriage shaft. As illustratedin FIG. 6, it is also possible to employ the carriage shaft 55 which hasa shape of a polygonal column having a cross section of a triangle, aquadrangle and so on. It is further possible to precisely determine adirection in which the pressure developing unit 80 moves by forming thegroove 56 along which the second rotating member 82 rolls in thecarriage shaft 55.

Third Embodiment

The cycolor medium 1 had, generally, exposed areas extend along fouredges of the medium 1 for constituting a blank (white) frame of apredetermined width. In this case, it is almost unnecessary to considerdeveloping the edge portions of the medium. On the other hand, it isconsidered to make the entire area of the medium available to users sothat the recorder can expose the areas extending along four edges of themedium. Accordingly, it is also desired that the pressure developingunit be capable of performing pressure development by applying ahomogeneous pressure to the areas extending along the edges of themedium.

As illustrated in FIG. 7, the platen 11 is pressed against the firstrotating member 71 by an elastic member such as a coil spring 14. Theplaten 11 can apply a suitable pressure to the medium 1 of moderatethickness when it is inserted between the platen 11 and the firstrotating member 71. In addition, since the platen 11 is elasticallysupported to generate a sufficient pressure, it is possible to performdevelopment under a suitable pressure, even if the medium 1 varies inthickness. Even if the first rotating member 71 has erection tolerancesor is slightly worn away, it is possible to obtain a pressure sufficientto perform development without any problem.

As illustrated in FIG. 7, when the pressure developing unit 70 passes anedge 1a of the medium 1, the coil spring 14 pushes the platen 11 so asto compensate for lack of the thickness of the medium 1. Thus, thecontact between the platen 11 and the first rotating member 71 is kept.Conversely, when the pressure developing unit 70 runs onto the edge 1aof the medium 1, the coil spring 14 contracts so as to compensate forthe thickness of the medium 1, whereby the pressure developing unit 70can perform pressure development of the medium 1 under a suitablepressure. If the coil spring 14 extends or contracts when the pressuredeveloping unit 70 runs onto the edge 1a of the medium 1, the platen 11may slightly vibrate. In the case where the areas extending along theedges 1a of the medium 1 constitute a blank frame, it is unnecessary toperform pressure development of those areas. Therefore, no problem iscaused. However, in the case where the areas in the vicinity of theedges 1a of the medium 1 are available to users, if the platen 11vibrates in the vicinity of the edges 1a, the pressure applied to themedium 1 may fluctuate enough to cause a color shade or irregularity.That is, the color image thus developed may have streaks of differentcolor densities along the edges 1a of the medium 1.

As illustrated in FIG. 8, if a guide plate 15 that is almost as thick asthe medium 1 is disposed on the platen 11 along the edge 1a of themedium 1, it is possible to almost completely eliminate the influencesof vibration of the platen 11 exerted when the first rotating member 71passes the edge 1a of the medium 1. Accordingly, it is possible toperform pressure development under a homogeneous pressure even in thevicinity of the edges 1a and to prevent the generation of a colorirregularity. However, this system requires that the medium 1 beconveyed precisely enough to prevent the first rotating member 71 fromfalling into a gap between the guide plate 15 and the edge 1a. However,if a minute angular deviation (skew) is caused in conveying the medium1, the edge 1a of the medium 1 and the guide plate 15 may easily overlapor form therebetween a gap into which the first rotating member 71 tendsto fall. Therefore, the method as illustrated in FIG. 8 may not reliablyprevent the generation of color nonuniformity.

FIG. 9 schematically illustrates another example of the pressuredeveloping mechanism 90 of the present invention. Those components thatare commonly used in the foregoing and following embodiments are denotedby the same reference numerals, and the detail thereof will bedescribed. In this pressure developing unit 70, a coil spring 91 isdisposed between the first rotating member 71 for pressurizing themedium 1 and the second rotating member 72 moving by revolving along thecarriage shaft 52 being a supportive member. Therefore, the coil spring91 elastically transmits a load applied to the first rotating member 71to the second rotating member 72. When the first rotating member 71 runsonto the edge 1a of the medium 1, the coil spring 91 contracts so thatthe pressure developing unit 70 of the present example can develop themedium 1 under a suitable pressure. Since this pressure developing unit70 has the coil spring 91 extends or contracts when the first rotatingmember 71 runs onto the edge 1a of the medium 1, the first rotatingmember 71 may tend to vibrate, nevertheless, non of color irregularitiesoccur in the areas extending along the edges 1a. Thus, it is possible toobtain a clear color image having no streaks of different colordensities. In the pressure developing unit 70 of the present embodiment,it is the first rotating member 71 that is elastically supported, andthe first rotating member 71 is much lighter than the platen 11.Therefore, even if the first rotating member 71 runs onto the edge 1aand vibrates, such vibration is rapidly damped and thus does notadversely affect the quality of pressure development. This is regardedas the reason why a clear color image can be obtained.

By elastically connecting the first rotating member 71 with the secondrotating member 72 in this manner, the pressure developing unit 70 ofthe present example absorbs the thickness of the medium 1. In addition,it is also possible to perform pressure development of the medium 1under a suitable pressure even if the first rotating member 71 haserection tolerances or is worn away. Accordingly, the pressuredeveloping mechanism 90 of this example can fix the platen 11 withoutelastically supporting it, which platen is a sheet-supporting memberthat holds the recording sheet 1 from the side opposite to the firstrotating member 71. Therefore, vibration of the platen 11 can beprohibited. Consequently, it is possible to prevent color nonuniformitybeing caused in the vicinity of the edges 1a of the medium 1, and toactually expose the areas extending along the edges 1a of the medium 1.Thus, it is possible to abolish a blank frame on the cycolor medium 1and to provide the medium 1 which can be used all over by a user, arecorder and a printing method therefor. Hence, the user can obtain acolor print on which an image stretches all over.

In addition, as is the case with the aforementioned pressure developingunit, in this pressure developing unit 70, it is also designed totransmit a load applied to the first rotating member 71 to the secondrotating member 72 which moves by revolving along the carriage shaft 52.Therefore, the pressure developing unit 70 can be moved with aconsiderably small driving force. Thus, as is the case with theaforementioned examples, the pressure developing unit 70 of the presentexample can realize a recorder that is compact in size, light in weight,suited for conveyance and usable with low power consumption. Further, itis possible to provide a recorder that print that can produce a colorprint with no blank frames using a cycolor medium 1.

FIG. 10 illustrates still another example of the pressure developingmechanism 90 according to the present invention. In the pressuredeveloping unit 70 of the present embodiment, a center of rotation 72oof the second rotating member 72 is offset relative to a center ofrotation 71o of the first rotating member 71. These first and secondrotating members 71 and 72 are supported by first and second arms 92 and93 respectively, which are different in length. In addition, the arms 92and 93 are elastically connected with each other by the coil spring 91.

The pressure developing unit illustrated in FIG. 9 has the first andsecond rotating members 71 and 72, and the coil spring 91 linearlyarranged, so that the distance between the first and second rotatingmembers 71 and 72 is large. Therefore, the space between the carriageshaft 52, along which the pressure developing unit 70 reciprocates, andthe platen 11 is wider. Thus, the recorder needs to ensure an amplespace for accommodating the pressure developing unit 70, the carriageshaft 52 and the platen 11. On the other hand, the pressure developingunit 70 as illustrated in FIG. 10 adopts an arrangement in which thecenter of rotation 72o of the second rotating member 72 is displacedrelative to the center of rotation 71o of the first rotating member 71.Therefore, it is possible to make the distance between the carriageshaft 52 and the platen 11 shorter than in the case where the first andsecond rotating members 71, 72 are linearly arranged in a directionperpendicular to the platen 11. Accordingly, the pressure developingmechanism 90 can be installed in a narrow space. In particular, it ispossible to provide the pressure developing mechanism 90 suited torealize the recorder 10 being entirely thin. Further, as is the casewith the pressure developing unit as illustrated in FIG. 9, it ispossible to prevent color irregularities caused on the edges 1a byelastically connecting the first and second rotating members 71 and 72with the arms 92 and 93 respectively, using the coil spring 91 as anelastic member.

Although the pressure developing unit 70 as illustrated in FIG. 10 hasthe first and second rotating members 71, 72 spaced apart from eachother, it is also possible to arrange these rotary members 71 and 72 maycontact each other. Instead of the coil spring 91, a leaf spring or anelastic body made of other materials such as rubber can be used. It isalso evident in the other embodiments previously mentioned or to beexplained that other members can be used instead of the coil spring toobtain elasticity.

FIG. 11 illustrates still another example of the pressure developingmechanism 90 according to the present invention. The pressure developingunit 70 of the present embodiment has two pieces of the second rotatingmember 72a and 72b. In addition, a first rotating member 71 is disposedso as to contact both the second rotating members 72a and 72b. Therespective second rotating members 72a and 72b are elastically held bycoil springs 91a and 91b in a direction to reduce the distance betweenthe rotating members 72a and 72b. In this pressure developing unit 70,an arrangement in which centers of rotation of the second rotatingmembers 72a and 72b are offset with respect to a center of rotation ofthe first rotating member 71, is also adopted. Hence, it is possible toreduce the distance between the platen 11 and the carriage shaft 52.Further, the pressure developing unit 70 of the present embodiment isdesigned to absorb the thickness of the medium 1 due to an arrangementin which the first rotating member 71 increases the distance between thesecond rotating members 72a and 72b. Since the two rotary members 72aand 72b are elastically supported (held) in such a direction as toreduce the distance therebetween, the first rotating member 71 can bepressed against the medium 1 under a suitable pressure.

Accordingly, this pressure developing unit 70 is also able to smoothlymove past the edge 1a of the medium 1 and to perform pressuredevelopment of the medium 1 without generating color irregularities onthe medium 1. In addition, the two second rotating members 72a and 72bturn in a direction of moving of the pressure developing unit 70 alongthe carriage shaft 52. Therefore, as is the case with the pressuredeveloping units of the foregoing examples, this pressure developingunit 70 can be moved with a small driving force.

Although two pieces of the second rotating member 72 are provided in thepresent example, two pieces of the first rotating member 71 may also beprovided instead. In the case where two pieces of the first rotatingmember 71 are provided, it is desirable to elastically hold the firstrotating members so as to prevent increasing the distance between thetwo rotating members 71. In addition, the pressure developing unit 70may have more than three pieces of the first rotating members 71 or thesecond rotating members 72.

FIG. 12 illustrates still another embodiment of the pressure developingmechanism 90 according to the present invention. This pressuredeveloping mechanism 90 comprises the pressure developing unit 70 havingthe housing 79 in which the first rotating member 71 and the secondrotating member 72 are directly in contact with each other. The pressuredeveloping unit 70 is designed to reciprocate along the carriage shaft52 on the surface of the platen 11. Further, a metallic wire is providedas a guide member 95 along a route followed by the first rotating member71, therefore, the first rotating member 71 presses the recording sheet1 via the guide member 95. As the guide member 95, a thin deformablewire of metal or plastics or a thin band plate can be employed.

If the recording sheet exist, the deformable guide member 95 changes itsshape in accordance with a cross section of the recording sheet 1. Inthe vicinity of the edge 1a, the guide member 95 gradually deforms froma shape according to the platen 11 to a shape according to the recordingsheet 1. Thus, the shape of the guide member 95 is changed to relativelysmooth in comparison with the stair-like edge 1a of the medium 1. Hence,if the first rotating member 71 moving along the guide member 95 runsonto the recording sheet 1 from the platen 11, the coil spring 14elastically supporting the platen 11 is gradually displaced. Therefore,even if the platen 11 vibrates the moment the pressure developing unit70 has run onto the recording sheet 1, the amplitude of such vibrationbecomes considerably small. Thus, it is possible to inhibit pressurefluctuations in performing pressure development of the areas extendingalong the edges 1a so as to obtain a color image free from a color shade(nonuniformity, irregularity) even in those areas.

This pressure developing mechanism 90 also employs the pressuredeveloping unit 70 comprising the first and second rotating members 71and 72, and the pressure developing unit 70 can be moved with a smalldriving force. Accordingly, as is the case with the foregoing examples,the present pressure developing mechanism 90 is also suited to realize acompact recorder having a compact motor and being low in powerconsumption.

FIG. 13 illustrates still another embodiment of the pressure developingmechanism 90. The pressure developing mechanism 90 of the presentembodiment uses a number of small pieces 96 connected with one anotherby a superfine wire or the like as the guide member 95 for smoothlyguiding the first rotating member 71 of the pressure developing unit 70onto the recording sheet 1. By using a continuous member such as a wireas a guide member, the pressure developing mechanism as illustrated inFIG. 12 can inhibit pressure fluctuations when the first rotating member71 moves past the edge 1a. However, since the first rotating member 71pressurizes the recording sheet 1 via the guide member, the dimension ofcontact area of the guide member and the recording sheet 1 tends becomelarger than the contact area of the recording sheet 1 which is directlypressurized by the first rotating member 71. Therefore, the quality ofcolor development may deteriorate due to the lack of pressure. Or, toapply sufficient pressure for development to the recording sheet 1, theplaten 11 needs to be pressed against the pressure developing unit 70under a greater force. In that case, the resistance resulting fromrolling friction in moving the pressure developing unit 70 increases.

The pressure developing mechanism 90 illustrated in FIG. 13 employs asthe guide member 95 an assembly of the small pieces 96 connected withone another, which small pieces 96 can be slightly displaced withrespect to one another. Thus, the first rotating member 71 pressurizesthe recording sheet 1 over a limited area substantially corresponding tothe areas defined by the small pieces 96. The guide member 95 of thepresent example contacts the recording sheet 1 over a small area andthus can inhibit pressure reduction. Therefore, it is possible toprevent the quality of color development from being adversely affected,or to prevent the increasing the driving power for moving the pressuredeveloping unit 70 due to excess press from the platen 11.

As described based on the embodiments above, the pressure developingapparatus (unit) and the pressure developing mechanism according to thepresent invention have a first rotating member for pressurizing arecording sheet such as a cycolor medium that necessitates pressuredevelopment, and a second rotating member that transmits a load appliedto the first rotating member to a supportive member such as a carriageshaft and can rotate in a direction opposed to the first rotatingmember. These first and second rotating members revolve to the recordingsheet and the supportive member respectively in a directioncorresponding to a direction in which the pressure developing apparatusmoves. While rolling, the first rotating member applies a suitablepressure to the recording sheet. While rolling, the second rotatingmember can transmit a load applied to the first rotating member to thesupportive member. As described above, the first and second rotatingmembers do not need to have a spherical shape. A member that can rotate,turn or roll and the like, shaped like a disc, a roller or the like canbe used as the first rotating member and/or the second rotating member.The pressure developing apparatus and the pressure developing mechanismaccording to the present invention can eliminate those portions thatmove with sliding against to the recording sheet and/or the supportivemember. Accordingly, the pressure developing unit/apparatus is able toconsiderably smoothly move relative to the recording sheet. Thus, it ispossible to perform pressure development without developing flaws orwrinkles serious enough to damage the printing sheet. The pressuredeveloping apparatus moves along the supportive member, causing onlyrolling friction. Consequently, the amount of abrasion can be reduced,and the pressure developing apparatus can be moved with a considerablysmall driving force. As a result, in the present invention, a motor thatis compact and operable with low power can move the pressure developingapparatus. That is, the pressure developing apparatus according to thepresent invention is able to realize a recorder that is compact in sizeand operable with low power consumption.

In particular, the recorder adopting the pressure developing apparatusaccording to the present invention makes it possible to move both thepressure developing apparatus and the exposure apparatus by mountingthem on the carriage. And, all the motions including the motions fordisplacing the carriage, conveying the sheet and so forth can beachieved with a single motor. In addition, the pressure developingapparatus according to the present invention can reduce the drivingpower necessary for the carriage, which requires the greatest powerconsumption among those components controlled by the motor. Therefore,the only motor or the main motor of the recorder can be realized as acompact motor that is operable with low power. Thus, the pressuredeveloping apparatus according to the present invention makes itpossible to reduce the recorder in size, electric power andmanufacturing cost. Since the electric power consumption can besubstantially reduced, it is possible to realize a compact recorder thatis suited for conveyance and operable for a long period of time with apower source of limited energy such as a battery.

Further, the pressure developing apparatus according to the presentinvention can be accommodated in a thin narrow space, whereby it ispossible to reduce the recorder in size, particularly in thickness. Inaddition, the cycolor medium enables color printing withoutnecessitating the use of consuming supplies such as ink. Hence, it ispossible to provide the recorder having the pressure developingapparatus according to the present invention for using the cycolormedium as a recording medium being compact in size and capable of easilyperforming color printing at any time.

INDUSTRIAL APPLICABILITY

The pressure developing apparatus and the pressure developing mechanismaccording to the present invention are suited for a recorder thatperforms color printing on a recording medium such as a cycolor mediumthat requires pressure for printing. By employing the pressuredeveloping apparatus according to the present invention, it is possibleto provide a recorder that is compact in size, suited for personal useand operable at any time and at any place.

What is claimed is:
 1. A pressure developing apparatus moving along asupportive member to perform pressure development of a recording sheet,comprising:a first rotating member moving by revolving to pressurize arecording sheet; and a second rotating member moving by revolving withrespect to said supportive member to move therealong, said secondrotating member being able to transmit a load applied to said firstrotating member to said supportive member.
 2. A pressure developingapparatus according to claim 1, wherein said first rotating member movesby revolving while pressurizing the recording sheet and said secondrotating member moves by revolving between said first rotating memberand said supportive member while being in contact with said firstrotating member and said supportive member.
 3. A pressure developingapparatus according to claim 1, further comprising a transmissionapparatus elastically transmitting a load applied to said first rotatingmember to said second rotating member.
 4. A pressure developingapparatus according to claim 1, characterized by an arrangement in thata center of rotation of said second rotating member is offset relativeto a center of rotation of said first rotating member.
 5. A pressuredeveloping apparatus according to claim 1, wherein the pressuredeveloping apparatus has a plurality of said first or second rotatingmembers and at least one of said first or second rotating members movesby revolving while being in contact with a plurality of said second orfirst rotating members.
 6. A pressure developing apparatus according toclaim 5, further comprising a holding apparatus for applying an elasticforce in such a direction as to reduce a distance among said pluralityof first rotating members or among said plurality of second rotatingmembers.
 7. A pressure developing apparatus according to claim 1,wherein said supportive member is a carriage shaft extending in scanningdirections of the recording sheet.
 8. A pressure developing apparatusaccording to claim 1, wherein said first rotating member has a shape forcontacting the recording sheet over a narrow continuous area.
 9. Apressure developing mechanism having a pressure developing apparatusaccording to claim 1 and a sheet supporting member for supporting arecording sheet from a side opposite to said first rotating member,wherein said pressure developing apparatus moves along a defined path,and wherein a protrusion extends from the sheet supporting member alonga path which follows a path of movement of said first rotating membersuch that the recording sheet is pressurized against the protrusion. 10.A pressure developing mechanism having a pressure developing apparatusaccording to claim 1, a sheet supporting member for supporting arecording sheet from a side opposite to said first rotating member, anda pressure supporting apparatus for elastically supporting said sheetsupporting member to said first rotating member while applying pressurethereto.
 11. A pressure developing mechanism according to claim 10,wherein a guide member that is deformable into a smooth shape inaccordance with a cross section of the recording sheet is providedbetween said first rotating member and the recording sheet along adirection in which said first rotating member moves.
 12. A pressuredeveloping mechanism according to claim 11, wherein said guide member isa number of small divided pieces ranging along a direction in which saidfirst rotating member moves.
 13. A recorder comprising:a pressuredeveloping apparatus according to claim 1; an exposure apparatus forexposing a photosensitive recording sheet; a sheet-conveying apparatusfor conveying the recording sheet exposed by said exposure apparatus tosaid pressure developing apparatus; and a driving apparatus for causingsaid pressure developing apparatus to reciprocate along said supportivemember which extends in scanning directions substantially perpendicularto the sheet-conveying direction of said sheet-conveying apparatus. 14.A recorder according to claim 13, wherein said exposure apparatus isable to move along said supportive member and said driving apparatuscauses said exposure apparatus to reciprocate together with saidpressure developing apparatus along said supportive member.
 15. Apressure developing apparatus for performing pressure development of arecording sheet, comprising:a supportive member extending along apressure developing location; a first rotating member moving byrevolving to pressurize the recording sheet; and a second rotatingmember moving by revolving relative to said supportive member as itmoves therealong, said second rotating member being positioned totransmit a load applied to said first rotating member to said supportivemember, and said first rotating member moving with said second rotatingmember in a direction defined by said supportive member.
 16. A pressuredeveloping apparatus for performing pressure development of a recordingsheet which moves along a defined path, comprising:a supportive memberextending at least partially across the defined path of the recordingsheet; a first rotating member moving at least partially across thedefined path of the recording sheet by revolving to pressurize therecording sheet; and a second rotating member moving at least partiallyacross the defined path of the recording sheet by revolving with respectto said supportive member, said second rotating member transmitting aload applied to said first rotating member to the supportive member, andsaid first rotating member moving with said second rotating member in adirection defined by said supportive member.